Liquid crystal display device characterized by its less power consumption and space-saving feature has been expanding its applications year by year. Patent Literature 1 describes an optical film used in the liquid crystal display device, the film having a degree of substitution by acetyl group of 2.0 to 2.6, having both ratios of content of xylose and mannose relative to acetyl cellulose of 0.9% by mass or below, and containing a triazine-base retardation enhancer, a monosaccharide or disaccharide compound, and wavelength dispersion modifier. Patent Literature 2 describes a film containing a cellulose acylate with a total degree of substitution of 1.5 to 2.6 and a sugar ester, being thin, having optical performance developability, and showing a low level of internal haze.
Patent Literature 3 describes a cellulose film showing a dimensional change rate of −0.5% to +0.5% after allowed to stand in a 60° C./90% relative humidity atmosphere for 24 hours, and the film also reduces changes in black luminance in oblique view after allowed to stand at 60° C./90% relative humidity for 500 hours. Patent Literature 4 describes a polymer film having the front and back surfaces differed in wavelength dependence of refractive index anisotropy and/or refractive index anisotropy.